This empirical study investigates the factors influencing Nigerians’ trust and adoption of mobile banking technology; using an integrative model. Research was conducted using a questionnaire developed and distributed in Nigeria. Out of 2256 returned questionnaires, 1725 were deemed to have been completed and hence usable. The data was analysed using confirmatory factor analysis and the results showed that confidentiality, integrity, authentication, access control, best business practices and non-repudiation significantly influenced technology trust with availability showing unsatisfactory values for consideration. In addition, technology trust showed a direct significant influence on perceived ease of use and usefulness. Technology trust also showed an indirect influence on intention to use through its impact on perceived usefulness and perceived ease of use. Also, perceived ease of use and perceived usefulness showed significant influence on consumer’s intention to adopt the technology. As a result of increased understanding of customer trust and adoption trends in Nigeria, these findings have important theoretical implications for researchers with interests in technology acceptance trends and the role of external factors, such as trust, in user adoption of technology. Such implications include the provision of empirical data, which highlights the role technology trust, demographic segmentations, perceived ease of use and perceived usefulness play in mobile banking adoption in Nigeria. In addition, the successful completion of this study provides justification for the use of this research’s model as a suitable framework for investigating user adoption of technology.

Multiphase flow can be defined as the simultaneous flow of a stream of two or more phases. Solids-in-water flow is a multiphase flows where solids and liquid are both present. Due to the density differences of the two phases, the results for such flow is often to have non-uniform profiles of the local volume fraction and local axial velocity for both phases in the flow cross-section. These non-uniform profiles are clearly noticeable in solids-in-water stratified flow with moving bed for inclined and horizontal pipelines. However in many industrial applications, such as oil and gas industry, food industry and mining industry, multiphase flows also exist and it is essentially important to determine the phase concentration and velocity distributions in through the pipe cross-section in order to be able to estimate the accurately the volumetric flow rate for each phase. This thesis describe the development of a novel non-intrusive flow meter that can be used for measuring the local volume fraction distribution and local axial velocity distributions of the continuous and discontinuous phases in highly non-uniform multiphase flows for which the continuous phase is electrically conducting and the discontinuous phase is an insulator. The developed flow meter is based on combining two measurement techniques: the Impedance cross correlation ICC technique and the electromagnetic velocity profiler EVP technique. Impedance cross correlation ICC is a non-invasive technique used to measure the local volume fraction distributions for both phases and the local velocity distribution for the dispersed phase over the pipe cross-section, whilst the electromagnetic velocity profiler EVP technique is used to v measure the local axial velocity profile of the continuous phase through the pipe cross-section. By using these profiles the volumetric flow rates of both phases can be calculated. A number of experiments were carried out in solid-in-water flow in the University of Huddersfield solids-in-water flow loop which has an 80 mm ID and an approximately 3m long working section. ICC and EVP systems were mounted at 1.6 m from the working section inlet which was inclined at 0 and 30 degree to the vertical. The obtained result for the flow parameters including phase volume fraction and velocity profiles and volumetric flow rates, have been compared with reference measurements and error sources of difference with their reference measurements have been identified and investigated.

Complex design specifications and tighter tolerances are increasingly required in modern engineering applications, either for functional or aesthetic demands. Multiple sensors are therefore exploited to achieve both holistic measurement information and improved reliability or reduced uncertainty of measurement data. Multi-sensor integration systems can combine data from several information sources (sensors) into a common representational format in order that the measurement evaluation can benefit from all available sensor information and data. This means a multi-sensor system is able to provide more efficient solutions and better performances than a single sensor based system. This thesis develops a compensation approach for reverse engineering applications based on the hybrid tactile-optical multi-sensor system. In the multi-sensor integration system, each individual sensor should be configured to its optimum for satisfactory measurement results. All the data measured from different equipment have to be precisely integrated into a common coordinate system. To solve this problem, this thesis proposes an accurate and flexible method to unify the coordinates of optical and tactile sensors for reverse engineering. A sphere-plate artefact with nine spheres is created and a set of routines are developed for data integration of a multi-sensor system. Experimental results prove that this novel centroid approach is more accurate than the traditional method. Thus, data sampled by different measuring devices, irrespective of their location can be accurately unified. This thesis describes a competitive integration for reverse engineering applications where the point cloud data scanned by the fast optical sensor is compensated and corrected by the slower, but more accurate tactile probe measurement to improve its overall accuracy. A new competitive approach for rapid and accurate reverse engineering of geometric features from multi-sensor systems based on a geometric algebra approach is proposed and a set of programs based on the MATLAB platform has been generated for the verification of the proposed method. After data fusion, the measurement efficiency is improved 90% in comparison to the tactile method and the accuracy of the reconstructed geometric model is improved from 45 micrometres to 7 micrometres in comparison to the optical method, which are validated by case study.

Civilisation has depended on welded structures to facilitate production and improve the quality of life. Welds are used to create infrastructure upon which we rely, such as transportation, oil and gas piping, shipbuilding, bridges and buildings, and to produce the equipment that makes all of this happen. In short, the joining of two metals through welding has immensely contributed to our society. A critical factor in the strength of welded joints is the geometry of the joints, and for this reason a robust optimisation of geometrical parameters of welded joints has been conducted in order to establish the optimum and most robust design in the presence of variation amongst geometrical parameters. A parametric finite element analysis, using Python script, has been performed with the objective to investigate the effect of the welded joint parameters on the stress concentration factors under tensile and bending load. The results indicate that the parametric model, which is generated by Python script, can be used in a wide range of welded geometry, and has the capacity to reduce the time of computation. Additionally, an experimental study, including the geometrical identification of the welded joints, tensile test, hardness test and fatigue, has also been performed. In order to select the best optimisation algorithms, different optimisation algorithms and performance metrics with various types of problem were examined in this study. The results from this part show the accuracy of Circumscription Metric (CM) in comparison to Pair wise Metric (PW) - which is used widely in optimisation studies. Furthermore, the results show that the Fast Multi-objective Optimisation Algorithm (FMOGA-II) outperformed other optimisation algorithms used during this study. In this study, a new methodology for selecting the most robust designs from within the Pareto set has been developed. Finally, a traditional and robust optimisation of a butt welded joint has been performed by establishing a link between an optimisation software package and parametric finite element, the results of which show the ability of this approach to extract the robust optimal designs from the Pareto front.

The objective of this thesis is to introduce a new method for identifying and detecting Intellectual Property (IP) in digital devices. The technology operates by inserting a small, low powered digital tag into a digital design; the tag is detected using temperature as a novel covert communications channel. The IP detection technology is a non-destructive, simple to use method which quickly detects the IP via the digital device package and thus requires no prior knowledge of the system. The method is intended to be used alongside existing IP protection methods. This thesis focuses on four areas: proving that temperature can be used to communicate information by varying both the internal and external temperature of an electronic device; the development of an active tag using a range of internal digital heat generators; the design of a passive tag, using an internal heat sensor and an external heat source; the invention of a True Random Number Generator (TRNG) using the digital properties of a Field Programmable Gate Array (FPGA). This research was sponsored by Algotronix, a company which develops security IP Cores for use in FPGAs. Both the active tag and TRNG were incorporated into Algotronix’ award winning DesignTag product.

The rapidly expanding civil aerospace sector is subjected to ever increasing pressure to be both sustainable and competitive. The research reported in the current thesis forms a part of the significant R&D effort of Rolls-Royce in response to this pressure. A broad based approach is taken to evaluating compressor blade surface finish with the objective of improving manufacturing and operating efficiency. Technical developments made as part of the current work is also intended to support future research in this important field. Compressor blade surface finish is emulated in the lab to detail its topographical development through the critical final polishing stage of processing. Based on existing surface standards a new characteristic developmental pattern and nomenclature is described for this finishing process. In addition, ‘edge shadowing’ a novel surface texture distribution is reported showing mass finishing to be non-uniform over a flat surface. The surface texture of exemplar ’as manufactured’ compressor blades is assessed and a protocol for areal parametric characterisation is developed. The protocol includes consideration of; surface texture homogeneity, local & global sample weighting, sampling efficiency, and key characteristic areal parameters, with their specification levels and confidence intervals. This detailed examination of mass finishing and the surface texture it produces will help improve process control and optimise economy. To improve the ongoing assessment of compressor performance degradation in service, a series of recovered compressor blades are characterised. Predominantly automated techniques are developed to assess compressor blade side and leading edge character. Key trends in surface topography on individual blade surface regions are reported along with broader degradation trends throughout the compressor. Leading edges are shown to be characteristically prone to greater degradation and levels of surface roughness, though elevated leading edge roughness is better correlated with deposits than with erosion. Proper analysis of aerodynamic losses due to aerofoil surface roughness requires the use of techniques with conflicting requirements. Thus in the current context the replication of metallic test aerofoils in thermally insulating resin is required. A method for this replication and its validation are presented. To investigate the underlying mechanisms of drag loss due to surface roughness a series of rough test aerofoil surfaces were parametrically characterised and wind tunnel tested. The well-established but incomplete correlation between drag loss and mean surface roughness amplitude (Sa) is then refined with other selected parameters that more fully represent surface topography.

No description available.

Resonant tunnelling diode (RTD) is known to be the fastest electronics device that can be fabricated in compact form and operate at room temperature with potential oscillation frequency up to 2.5 THz. The RTD device consists of a narrow band gap quantum well layer sandwiched between two thin wide band gap barriers layers. It exhibits negative differential resistance (NDR) region in its current-voltage (I-V) characteristics which is utilised in making oscillators. Up to date, the main challenge is producing high output power at high frequencies in particular. Although oscillation frequencies of ~ 2 THz have been already reported, the output power is in the range of micro-Watts. This thesis describes the systematic work on the design, fabrication, and characterisation of RTD-based oscillators in microwave/millimetre-wave monolithic integrated circuits (MMIC) form that can produce high output power and high oscillation frequency at the same time. Different MMIC RTD oscillator topologies were designed, fabricated, and characterised in this project which include: single RTD oscillator which employs one RTD device, double RTDs oscillator which employs two RTD devices connected in parallel, and coupled RTD oscillators which combine the powers of two oscillators over a single load, based on mutual coupling and which can employ up to four RTD devices. All oscillators employed relatively large size RTD devices for high power operation. The main challenge was to realise high oscillation frequency (~ 300 GHz) in MMIC form with the employed large sized RTD devices. To achieve this aim, proper designs of passive structures that can provide small values of resonating inductances were essential. These resonating inductance structures included shorted coplanar wave guide (CPW) and shorted microstrip transmission lines of low characteristics impedances Zo. Shorted transmission line of lower Zo has lower inductance per unit length. Thus, the geometrical dimensions would be relatively large and facilitate fabrication by low cost photolithography. A series of oscillators with oscillation frequencies in the J-band (220 – 325 GHz) range and output powers from 0.2 – 1.1 mW have been achieved in this project, and all were fabricated using photolithography. Theoretical estimation showed that higher oscillation frequencies ( > 1 THz) can be achieved with the proposed MMIC RTD oscillators design in this project using photolithography with expected high power operation. Besides MMIC RTD oscillators, reported planar antennas for RTD-based oscillators were critically reviewed and the main challenges in designing high performance integrated antennas on large dielectric constant substrates are discussed in this thesis. A novel antenna was designed, simulated, fabricated, and characterised in this project. It was a bow-tie antenna with a tuning stub that has very wide bandwidth across the J-band. The antenna was diced and mounted on a reflector ground plane to alleviate the effect of the large dielectric constant substrate (InP) and radiates upwards to the air-side direction. The antenna was also investigated for integration with the all types of oscillators realised in this project. One port and two port antennas were designed, simulated, fabricated, and characterised and showed the suitability of integration with the single/double oscillator layout and the coupled oscillator layout, respectively.

Reinforced concrete is one of the most commonly used structural materials in the world and is used for buildings and many different types of civil engineering structures, such as bridges, tunnels and airports. The majority of these structures are required to remain in service for at least 50 years while some are expected to last well over 100 years. Fracture of these structures leads to an increase in the permeability of the concrete which in turn can result in increased ingress of water and other aggressive agents, such as chlorides or carbon dioxide, that accelerate the deterioration of these structures. Likewise, the mechanical properties of the concrete can be affected by the transport of moisture into the structure. The increase in moisture can lead to a reduction of the strength and the stiffness of the material. The costs arising from structural failure are extremely high and in practice repair work tends to be implemented even when it is not entirely necessary. Therefore reliable approaches that can describe the interaction between the transport and mechanical properties of concrete and predict resulting structural degradation are of great benefit for practising engineers. Numerical models, such as the one proposed in this work, could be used for predicting when a repair is really necessary. In this work, a transport-mechanical lattice approach to modelling the durability of concrete is proposed. The discretisation of the specimen domain is based on a dual Delaunay and Voronoi tessellation in which the edges of the Delaunay triangles form the mechanical elements and the transport elements are placed along the edges of the Voronoi polygons. The mechanical response of the concrete is described using an isotropic damage constitutive law, while the transport of moisture through the specimen is described using constitutive laws developed for mass transport through porous materials. Both the mechanical and the transport models are assessed individually before the coupling ii between the two models is implemented. The accuracy of the proposed coupled approach is validated through the analysis of an elastic thick-walled cylinder, in which the numerical results are compared with an analytical solution derived as part of this work. The proposed coupled approach is then applied to the case of corrosion-induced cracking of reinforced concrete structures. In this approach, the corrosion products are assumed to behave as a fluid and therefore values of fluid properties are required. A value of viscosity is determined based on the analysis of a concrete specimen containing a single reinforcement bar. Finally, the proposed approach is applied to a concrete specimen containing four reinforcement bars to assess the approach as a predictive model. As expected with the concrete specimen containing a single reinforcement bar, very good agreement between numerical and experimental results is obtained. In the case of a specimen containing four reinforcement bars, it is observed that for small attack penetration depths the proposed approach is in very good agreement with experimental results. As the analysis continued, however, the numerical approach under-estimated the crack width when compared to experimental results.

No description available.